• Journal of International Academy of Physical Therapy Research
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• v.12 no.1
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• pp.2302-2307
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• 2021

Background: Patients with lumbar spinal stenosis show abnormal changes in muscle activity due to pain and limited range of motion of the lumbar spine. Excessive increased muscle tone and decreased muscle activity patterns threaten the patients' quality of life. However, there have been a few studies showing how to improve muscle performance in patients with lumbar spinal stenosis. Among these, joint mobilization is one way of improving muscle performance through pain relief and increasing the range of motion. Objectives: To investigate the effect of lumbar mobilization by orthopedic manual physical therapy on paravertebral muscle activity and tone in patients with lumbar spinal stenosis. Design: A randomized controlled trial. Methods: In this study, 24 patients with lumbar spinal stenosis were randomized (1:1 ratio) into two groups. The experimental group underwent lumbar posteroanterior mobilization, and the control group underwent conventional physical therapy (conventional transcutaneous electrical nerve stimulation) for 15 minutes each. For outcome measures, Myoton^®PRO was used to evaluate muscle tone when resting of the paravertebral muscle in the pain area. For muscle activity evaluation, the reference voluntary contraction of the paravertebral muscle was evaluated using surface electromyography. Results: Muscle tone and activity were significantly improved after intervention in both the experimental and control groups. In addition, the experimental group showed more significant decrease in muscle tone and activity than the control group. Conclusion: These results suggest that lumbar mobilization improving muscle performance in patients with lumbar spinal stenosis.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.3
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• pp.142-152
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• 2014

Vehicular Ad-hoc Networks (VANETs) are comprised of wireless mobile nodes characterized by a randomly changing topology, high mobility, availability of geographic position, and fewer power constraints. Orthogonal Frequency Division Multiplexing (OFDM) is a promising candidate for the physical layer of VANET because of the inherent characteristics of the spectral efficiency and robustness to channel impairments. The susceptibility of OFDM to Inter-Carrier Interference (ICI) is a challenging issue. The high mobility of nodes in VANET causes higher Doppler shifts, which results in ICI in the OFDM system. In this paper, a frequency domain com-btype channel estimation was used to cancel out ICI. The channel frequency response at the pilot tones was estimated using a Least Square (LS) estimator. An efficient interpolation technique is required to estimate the channel at the data tones with low interpolation error. This paper proposes a robust interpolation technique to estimate the channel frequency response at the data subcarriers. The channel induced noise tended to degrade the Bit Error Rate (BER) performance of the system. Parallel concatenated Convolutional codes were used for error correction. At the decoding end, different decoding algorithms were considered for the component decoders of the iterative Turbo decoder. A performance and complexity comparison among the various decoding algorithms was also carried out.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.3
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• pp.43-47
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• 2017

PURPOSE: The purpose of this study was to identify the effects of physical therapy plus Kinesio taping (KT) on muscle tone and stiffness in patients with shoulder pain. METHODS: This study included 22 participants who were divided into the experimental group (n=11) who underwent a routine physical therapy with KT and the control group (n=11) who received the same physical therapy only. The physical therapy consisted of heat application and electrical stimulation. Heat was applied for 10 minutes and electrical stimulation was conducted for 20 minutes. Intervention was provided over a 1-week period, and frequency for muscle tone and stiffness was measured to determine changes in shoulder muscle status. The muscles were supraspinatus and deltoid. Measurements were taken before, after 1day, 3day and after 1 week to identify time-dependent effects of intervention. RESULTS: The effects of the intervention were significant in both groups, and effects were greater in the experimental group. Changes in muscle tone and stiffness were statistically significant in both groups and at varying time points (p<.05). CONCLUSION: Based on the improved muscle performance found in this study, KT is considered an effective intervention strategy for patients with shoulder pain when it is combined with conventional physical therapy.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.3
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• pp.55-64
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• 2023

PURPOSE: Examine the effects of auditory feedback and functional electrical stimulation on balance, walking ability, and lower extremity function of subacute stroke patients. METHODS: Twenty-seven subjects diagnosed with subacute stroke within six months were randomly divided into three groups: test group 1, which performed walking exercises with auditory feedback and functional electrical stimulation; test group 2, which performed walking exercises only with functional electrical stimulation; control group applied only functional electrical stimulation, with nine subjects each. RESULTS: There were significant pre- to post-intervention differences in BBS in the gait training group with auditory feedback and functional electrical stimulation treatment, and significant pre- to post-intervention differences in BBS, sit-to-stand time, and average step speed in the gait training group with functional electrical stimulation, but no statistically significant differences in between-group comparisons. CONCLUSION: Gait training with auditory feedback and functional electrical stimulation can improve the balance and gait performance in stroke patients. Therefore, in the future, gait training with auditory feedback and functional electrical stimulation therapy may be suggested as a gait rehabilitation training tool for stroke patients.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.1
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• pp.96-103
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• 2005

To analyze the reason of aging deterioration in transmission line insulators, we performed a various kind of test and investigated mechanical and electrical characteristics of insulators. Test samples consisted of K-1989(36,000lbs), K-1995(36,000lbs) and K-2001(36,000lbs) type insulators which have been used in domestic 154 kV transmission lines. As a result of this test, the facts turned out K-2001 insulator which contain 17 wt.% alumina has better physical characteristics than K-1989 insulator which contain 8 wt% alumina. Relativity density and fracture toughness of K-1989 porcelain are 94.2 % and 1.4 MPa\ulcornerm$^{1}$2// but relativity density and fracture toughness of K-2001 porcelain are 96 % and 1.7 MPa\ulcornerm$^{1}$2//. K-2001 insulators show a good performance not only in a physical property test but also in power arc test and steep front of wave flashover test which is performed to evaluate electrical characteristics.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.115-118
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• 2007

Recently, the development of LEDs is important and prevalent in the lighting market. The purpose of this study is to evaluate the performance of white LEDs by comparing with fluorescent lightings. First, this study performed to survey technical developments and design trend of white LEDs. Second, comparing white LEDs with fluorescent lightings which are widely used, this paper evaluated physical characteristics of white LEDs. Lastly, this study Performed subjective evaluation which is comparing side-by-side rooms installed LEDs and fluorescent luminaires to investigate psychological and physical evaluation. The results of this study could be used as fundamental data for the development of white LEDs.

• Carbon letters
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• v.17 no.1
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• pp.39-44
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• 2016

The work presented in this report was a detailed comparative study of the electrochemical response exhibited by graphite anodes in Li-ion batteries having different physical features. A comprehensive morphological and physical characterization was carried out for these graphite samples via X-ray diffraction and scanning electron microscopy. Later, the electrochemical performance was analyzed using galvanostatic charge/discharge testing and the galvanostatic intermittent titration technique for these graphite samples as negative electrode materials in battery operation. The results demonstrated that a material having a higher crystalline order exhibits enhanced electrochemical properties when evaluated in terms of rate-capability performance. All these materials were investigated at high C-rates ranging from 0.1C up to 10C. Such improved response was attributed to the crystalline morphology providing short layers, which facilitate rapid Li⁺ ions diffusivity and electron transport during the course of battery operation. The values obtained for the electrical conductivity of these graphite anodes support this possible explanation.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.839-842
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• 1992

This paper describes an improved analytic model for a gallium-arsenide MESFET computer simmulation and deals with application to microwave performance. The current-voltage characteristics, the dependence of the capacitances, transconductances and drainconductances on bias conditions and the dependences of s-parameters on various frequencies are calculated. The model is base on a physical picture revealed through two-dimensional numerical analysis, and takes into account transition region and diffusion process under gate but it require a very small computer time. Simulation results agree well with the experimental data found earlier by other author The proposed model can be used for a computer-aided design of GaAs MESFET devices and for a study of application to microwave performance.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.3
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• pp.204-212
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• 2020

In this study, device suitability analysis is performed by comparing the performance of SiC MOSFET and GaN Transistor, which are WBG power semiconductor devices in the induction heating (IH) system. WBG devices have the advantages of low conduction resistance, switching losses, and fast switching due to their excellent physical properties, which can achieve high output power and efficiency in IH systems. In this study, SiC and GaN are applied to a general half-bridge series resonant converter topology to compare the conduction loss, switching loss, reverse conduction loss, and thermal performance of the device in consideration of device characteristics and circuit conditions. On this basis, device suitability in the IH system is analyzed. A half-bridge series resonant converter prototype using the SiC and GaN of a 650-V rating is constructed to verify device suitability through performance comparison and verified through an experimental comparison of power loss and thermal performance.

• Advances in nano research
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• v.15 no.3
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• pp.253-261
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• 2023

This study investigates the application of nano-composite materials in physical education, specifically focusing on improving the performance of sports hall flooring. The research centers on carbon nanotube reinforced polyvinyl chloride (PVC) composites, which offer enhanced mechanical properties and durability. The incorporation of carbon nanotubes as reinforcements in the PVC matrix provides notable benefits, including increased strength, improved thermal stability, electrical conductivity, and resistance to fatigue. The key parameters examined in this study are the weight percentage of carbon nanotubes and the temperature during the fabrication process. Through careful analysis, it is found that higher weight percentages of carbon nanotubes contribute to a more uniform dispersion within the PVC matrix, resulting in improved mechanical properties. Additionally, higher fabrication temperatures aid in repairing macroscopic defects, leading to enhanced overall performance. The findings of this study indicate that the utilization of carbon nanotube reinforced PVC composites can significantly enhance the strength and durability of sports hall flooring. By employing these advanced materials, the safety and suitability of physical education environments can be greatly improved. Furthermore, the insights gained from this research can contribute to the optimization of composite material design and fabrication techniques, not only in the field of physical education but also in various industries where composite materials find applications.